98 1NJUKIOIS AND HKNKKICIAL INSECTS OF CALIFORNIA. 



THE GREEN PEACH APHIS 

 Rhopalosiphum persiecB (Sulzer) 



[Myzus ixrsicw (Sulzer)] 



(Aphis persiecB Sulzer) 



(Rhopalosiphum dianthi Schrank) 



(Myzus achyrantes Monell) 



(Fig. 7 9) 



Description.— The color of this species varies from yellowish to 

 rich green. The winged form has a dark olive-green head, thorax 

 and a prominent dark patch on the dorsum of the abdomen as shown 

 in Fig. 7!). The apterous form is pale green or yellow without dark 

 markings. The adults are of medium size, varying from 1-16 to 1-12 

 inch in length. 



Fig. 79. — The green peach aphis, Rhopalosiphum persicce fSulz). Winged and apterous 

 females. Greatly enlarged. (Author's illustration, P. C. Jr. Ent. ) 



Life History. — The spring forms hatch from eggs deposited the 

 previous fall, just when the new foliage begins to appear. All twigs, 

 and especially the tender growths, are quickly attacked. Breeding con- 

 tinues throughout the entire spring and summer on any of the host 

 plants. In the fall males and females appear, and, mating, give rise to 

 the wintering eggs and the next year's broods. More commonly they 

 feed upon weeds throughout the winter and do not go through the egg 

 stage in California, as in colder climates. 



Distribution.— This aphis occurs throughout the entire State. 



Food Plants.— Amsinckia spectabilis, apricot, cabbage, carnation, 

 cauliflower, celery, cherry, chrysanthemum, citron, cucumber, egg- 

 plant, grapefruit, groundsel, hound 's-tongue, English ivy, lemon, 

 lettuce, false mallow, malva, mustard, nettle, orange, peach, pepper, 

 pigweed, plum, Bullace-plum, potato, radish, rhubarb, shepherd's purse, 

 snap dragon, sow-thistle, spinach, turnip, tomato and English walnut 

 are among a large list of plants attacked by the green peach aphis. 



THE SMALL GREEN ROSE APHIS 



Myzus rosarum (Walker) 63 



(Aphis rosarum Walker) 



(Fig. 80) 



Description. — Tli is louse is yellow or light green with dark mark- 

 ings on the adults as shown in Fig. 80, and only about half as large 



"W. M. Davidson also records Rhopalosiphum nervatum Gillette as quite injurious 

 to roses at Walnut Creek, Contra Costa County. This species greatly resembles Myzus 

 rosarum (Walker), but is somewhat larger and has conspicuous black nervures or 

 veins in the wings. 



